Piston and piston-pin construction



April 12 1927. 1,623,972

H. W. PIERCE PISTON AND PISTON PIN CONSTRUCTION Filed Jxine 12. 1924 7/W%w2i /zwaaw A TTORNEYS.

Patented Apr. 12, 1927. I v UNITED STATES ATENT' OFFICE.

HOW'ARD W. PIERCE, 01 BUTTE, MONTANA, ASSIG'NOB/ TO LOUIS M, STELL'MANN, OE

ONONDAGA COUNTY, NEW YORK. i

PISTON AND TLISTON-IIN CONSTRUCTION. Application filed June 12, 1924. Serial No. 719,669.

This invention relates to a construction of ing a bearing in or fitting in the pin bosses;

bearing for use where the temperature conand l is the connecting rod having a bearing ditions to which the bearing is subject in its 5 on the pin 3 between the pin bosses 2.

normal use, vary considerable, such as the As is well known to those skilled in the 5 bearings between the piston of an internal art, it is impractical to work together two 60 combustion engine and the piston pin and parts of the same metal, one on the other, 'as the connection rod, and has for its object steel on steel, or aluminum on aluminum, or particularly a bearing between pistons of a brass on brass, etc, and that two difierent metal or metal alloy having high coe'liicient metals of even slightly different character of expansion, such as so-called aluminum will under the widely Varying temperatures, (35

pistons, and a piston pin of a combination under which an internal combustion engine of metals difiierent from the piston and suit operates, develop widely varying clearances, able to coact with the bearings of an alumiespecially when the piston is of metal as alunum or alloy piston, all whereby a constant minum having a relatively high coeflicient 1 clearance is maintained at all varying tem of expansion. 70 Jeratures to which the piston is subjected. The pin 3 is preferably formed of two The invention consists in the novel ieametals combined to have the same expansion tures and in the combinat ons and construcratio as that of the piston under the varying tions hereinafter set forth and claimed. temperatures. and usually the pin is formec I d ibi thi i ti n f nce is with a core f aluminum and an outer shell had to the accompanying drawings in which which is mechanically expansible and con like characters designate corresponding tractible to compensate for variations that parts in all the views. would otherwise occur between the shell and Figure 1 is a vertical sectional view of a the pin bosses 2.

ment otthis 7 designates the shell or sleeve which 18 piston provided with one embodi invention, usually oi steel or any other mechanically Figure 2 is a transverse sectional view expansible or contractible metal, the sleeve oximately on l1ne 2'2, Fig. 1. being slotted lengthwise as. at 8 to render 1 Fig, 1, of anmechanically expansible and contractible, it

taken appr Figure 3 is a view similar to 30 other form of this invention. expanding under the thermal expansion oi Thi bearin construction comprise genthe core 6 and contracting on the core under erally the combination of two parts, one fithe contraction of the pin bosses 2 It also ting in the other, the parts being of metals expands under the influence of the core 6 to which owing to their ratio of expansion and fit the bearing 5 of the aluminum connecting 5 contraction under varying temperature conrod l, and contracts under the influence of ditions, maintain a normal clearance under the contractile bearing 5. Hence, the clearthe varying temperature conditions to which ance between the pm 3 and the pin bosses the parts are subjected in their normal use, and the connecting rod bearing will remain which clearance in other pistons varies substantially the same during all the varying widely at the various temperatures. temperatures to which they are subjecte My invention is here shown as embodied when embodied in an internal combustion in a piston construction for internal comengine. or other heat engine.

bustion or heat engines, which are subject, In Figure 3 the piston pin 9 instead of in normal use, to Widely varying temperabeing formed of two metal parts mechaniture conditions, as normal atmospheric temcally assembled may be tormed as a unit of a perature upon starting of engine when cold, combination of metals, that is, a metal alloy,

to the maximum temperature under which the metals of which are so proportioned as the engine operates, the piston being one of to have the same expansion ratio as that of the parts of the bearing construction and the the aluminum piston, or a piston of any '0 iston pin the other of the parts. other metal having relative high coefiicient 5 1 designates the piston formed of a metal of expansion. In such cases the pin may be of relatively high coetiicient or expansion as of aluminum alloy, bronze, etc.

aluminum or aluminum alloy. Ihe body of The pin may be mounted directly in the the piston is formed with piston pin bearpin bosses 2 or in a bushing as shown at 10,

55 ings or pin bosses 2. 3 is the piston pin havalso the connecting rod bearing 5 may be piston and piston pins,

loose, that is, may have a rocking movement relatively to the pin or may be clamped thereto as by a screw 12, in the usual manner.

Owing to this construction of bearing for the clearance between the pin and pin bosses and connecting rod caring Will remain substantially constant during all temperatures of the engine, and hence, there Will develop no undue looseness, noise, and knocks during the operation of e engine.

What I claim is:

1. In a piston, the combination of a pis ton body of a metal having a relatively high coeilicient of expansion, the piston body being formed with pin bosses, a. piston whereby a constant clearance is maintained between the pin, the pin bosses and the connecting rod bearing at all temperatures.

In a piston construction for internal combustion engines, a piston body of a metal having a relatively high coeflici'ent of expansion, the piston body being formed with pin bosses,a piston pin comprising a core of metal having a relatively high COGfilOlEIlt of expansion, and a mechanically expansible and contractile sleeve fitting the core and said bosses, and being mechanically expansible by the thermal expansion of the core and mechanically contractile by the contraction of the pin bosses, and acting to maintain a constant clearance between the pin and the piston bosses and the connecting rod hearing at all temperatures of the engine.

' In a. piston construction, the combination of a piston body of a metal having a relatively high coeflicient of expansion, the body being formed with pin bosses, a piston pin mounted in the bosses and a connecting rod having a bearing 011 of metal same ratio 01' piston bination of metals expansion as the pin bosses and the connecting rod bearing, whereby a constant clearance is maintained between the pin and the pin bosses and the connecting rod bearing at all ten'iperatures of the engine.

In testimony whereof, I have hereunto signed my name, at Butte, in the county of Silver Bow, and in State of Montana, this 28th day of May, 1924.

HOlVARD W'. PIERCE. 

